It costs $125 to nominate a book for a National Book Award. Why were so many more publishers willing to pay it for nonfiction than for fiction or poetry?

Do recent nonfiction books outshine novels? Many critics think so. And publishers seem to agree, based on their willingness to pay the $125-per-book entry fee for the National Book Awards.

The prize sponsor reports that in 2008 publishers nominated the following numbers of books by category: 540, nonfiction; 274, young people’s literature; 271, fiction; and 175, poetry. Publishers may have submitted nearly twice as much nonfiction as fiction because more of it gets published. Yet that explanation begs the question, because publishers presumably buy books for the same reason they nominate them for awards: They think they’re good.

More evidence of the superiority of nonfiction might seem to come from Wednesday night’s fiction winner: Peter Matthiessen’s Shadow Country, a reworking of an earlier trilogy. If this year’s novels had been stronger, would the judges have considered a book that includes previously published material? Was Matthiessen’s shortlisting a sign of desperation in judges who wanted a strong book on the final list even if it meant exhuming some work published as long ago as 1990?

Probably not. It’s more likely the judges wanted to reward a distinguished author in his 80s for his fiction and didn’t know if they’d have another chance. (Matthiessen won the 1980 National Book Award for nonfiction for The Snow Leopard.) It’s also possible that the judges just didn’t like some of the novels that many critics ranked among the best of the year, such as Netherland.

Then why did publishers nominate so much more nonfiction? Two possible explanations. One is that nonfiction books have more opportunity to catch fire in the media or elsewhere: They don’t depend on reviews as much as novels do. And publishers know that momentum can affect judges. In paying those $125 entry fees, some may have invested in what they considered the safest bets.

A related explanation for all the nonfiction nominees is that fiction has two main genres: novels and short stories. Nonfiction has many — including history, memoirs, biography, essays and journalism — and more ways to make an impact. This year’s nonfiction shortlist reflected some of them: The Dark Side (exposé), Final Salute (feature writing), This Republic of Suffering (social history), The Suicide Index (memoir), and the winner, The Hemingses of Monticello (family history).

Yet nonfiction dates faster than nonfiction. This is why novels tend to define their eras better than works of nonfiction do. So the answer to “Were this year’s novels better than the nonfiction books?” rests with history. Decades from now, this year’s best nonfiction books may have yielded to others that have more recent reporting or more up-to-date research, while some of the novels may seem as fresh as ever, just as Jane Austen’s do nearly two hundred years after they appeared.